Results/Discussion Continued:

Population Genetics and Dynamics of Caribbean Spiny Lobster (Panulirus argus) Phyllosoma in the Sargasso Sea

Jody Daniel1,2, Jeremy Pivor1,31 Sea Education Association, 2 St. George’s University, St. Georges, Grenada, 3 Washington University in St. Louis, St. Louis, Missouri

Methods:•Phyllosoma were collected aboard the SSV Corwith Cramer research cruise between May 14th – June 17th 2012 from St. Croix to Woods Hole, Massachusetts via Bermuda.

•A neuston net and meter net (~10m below the surface) were deployed at 0000 daily along a 1 nautical mile transect at 2 knots (Fig. 1).

•Temperature, salinity, and chlorophyll afluorescence were measured along the ship’s path.

•Phyllosoma were classified to species and life stage using the body length (BL), cephalic shield length (CL), cephalic shield width (CW), thorax width (TW), andmicroscopy (Fig. 2).

•Neural and muscle tissue were used for DNAextraction and sequenced using the hypervariable domain of the mitochondrial DNA control region (HV-CRd1) with the primers CRL-F and CRL-R.

•23 samples were sent for DNA sequencing,and consensus reeds with an 85% identity to P. argus were used for analysis.

Fig. 2: Diagram showing measurements of Panulirus argus phyllosoma. (Goldstein et al. 2008)

Fig. 1: Neuston net deployment

SSV Corwith Cramer

Abstract:The Caribbean Spiny Lobster, Panulrius argus, is widely distributed across the Atlantic Ocean and itsfishery is ranked as the second most economically important in the Central Atlantic region. Stocks havebeen decreasing since the early 21st century. Management of the fishery has been difficult given the wideuncertainty regarding Spiny Lobster population dynamics. The long-range dispersal of the planktoniclarvae, called phyllosoma, makes it difficult to determine P. argus population structuring. Uncertaintyregarding local or distant recruitment of lobster stocks has made it difficult to create managementstrategies. The Sargasso Sea may serve as critical habitat for phyllosoma in acting as a corridor betweenstocks in the Gulf of Mexico, Florida, South America, and the Caribbean. In our study we have explored theinfluence of selected environmental parameters on phyllosoma distribution, as well as genetic and life stagestructuring in the Sargasso Sea in order to understand Panulirus argus population dynamics. We found nosignificance between phyllosoma abundance and temperature, salinity, or chlorophyll a concentration.Examination of historical records from Sea Education Association 1979-2012 cruises and our data in theSargasso Sea revealed a narrow temperature range in which phyllosoma were found (18.0o-28.3oC).Additionally, the temporal variations of phyllosoma abundance from Sea Education Association archiveddata from 1985-2012 in the North and South Sargasso Sea was relatively variable. Life stage structuringand genetic analysis of the phyllosoma collected, and previously sequenced adults from Diniz et. al. 2005,(357bp) supports the Pan-Caribbean Panmictic theory of distant recruitment. This suggests the need forregional management of the Caribbean Spiny Lobster.

Results/Discussion:

V18%

VI14%

VII29%

VIII25%

IX7%

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Fig. 3: Proportion of phyllosoma P. arguslife stages collected from St. Croix to Bermuda (n=27). Figure shows that life stages 8 and 7 constituted 54% of the P. argus collected, while no phyllosoma below life stage 5 were found

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Fig. 4: Average phyllosoma collected at each station between 1985-2012 in the South and North Sargasso Sea. Figure shows that the average abundance of phyllosoma collected is highly variable.

Fig. 5: Number of phyllosoma collected along Sea Education Association cruises from 2010-2012 (diamond) in the Sargasso Sea, including P. argus from cruise C241 (St. Croix to Bermuda) (square), with respect to sea surface temperature. Figure shows that phyllosoma abundance from C241 was observed to peak at 26.3oC and ranged from 24.2-26.4 oC

Fig. 6: Number of phyllosoma collected along SEA Education Association cruises from 1979-2012 in the Sargasso Sea with respect to sea surface temperature. Figure shows an observed ecological trend of greater phyllosoma abundance within a narrow temperature range of 18.0o-28.3oC.

Fig. 8: Life stages and genetic lineages of phyllosoma collected at each station across latitude from St. Croix to Bermuda during cruise C241. Highest life stages (9 and 10) were collected in northern latitudes. Life stage structuring was relatively heterogeneous across the transect. Station 012 contained the greatest heterogeneity in life stages. The figure shows that 75% were associated with evolutionary linage 1 and 25% were related to evolutionary linage 2. Station 012 contained phyllosoma of both lineages 1 and 2. There were no genetic patterns found with increasing latitude.

Conclusions:•Distribution of phyllosoma may be limited or impacted by sea surface temperature.•Further analysis on the possible impact of salinity and chlorophyll a concentration are required.•The temporal variations of phyllosoma abundance in the North and South Sargasso Sea may be related to adult population dynamics or distant spawning events during the reproductive season, but do not match the decreasing trend of adult stocks.•Genetic analysis and life stage structuring from our study supports the Pan-Caribbean Panmictic theory versus the Closed System theory.

Policy Implications:Given the observed mixing of populations, and therefore support for the distant recruitment theory, a regional fisheries management approach may be a feasible option for the Caribbean Spiny Lobster fishery. Further research though is needed to determine stock origins in order to enable more specific regional collaboration.

Fig. 7: Maximum Likelihood tree describing evolutionary relationships among 32 P. argus haplotypes from (24 adults) Diniz et al 2005 and 8 phyllosoma (1 from C230A and 7 from C241) (highlighted), resolved on the basis of (357bp) HV-CRd1. Bootstrap values based on 1000 replicates representing all nodes. The tree shows that phyllosoma collected had similar genetic structuring to previously sequenced adults. No phyllosoma were genetically similar to the Brazil population. The figure also shows indiscrete population structuring of phyllosoma within lineages 1 and 2.

Lineage 1

Lineage 2

Brazil

Acknowledgments:The authors are thankful to the Sea Education Association for providing the transportation and equipment needed to carry out this research. We are also grateful to Dr. Amy Suida, Dr. Erik Zettler, Dr. Linda Amaral-Zettler and Ms. Annie Scoffield for their insightful advice and assistance during the study and data analysis period. We are also thankful to the crew of the SSV Corwith Cramer and the C-241 class for their support during our project (especially the cool, calm, collected C watch). Lastly, we are grateful to Mr. Greg Boyd and the Bermuda Aquarium, Natural History Museum and Zoo for providing us with neural tissue samples from adult lobsters for genetic analysis.

References:•Diniz, F.M., N. Maclean, M. Ogawa, I.H.A. Cintra, AND P. Bentzen. 2005. The hypervariable domain of the mitochondrial control region in Atlantic spiny lobsters and its potential as a marker for investigating phylogeographic structuring. Mar. Biotech. 7: 462-473, doi: 10.1007/s10126-004-4062-5.•Goldstein, J. S., H. Matsuda, T. Takenouchi, AND M. J. Butler IV. 2008. The complete development of larval Caribbean spiny lobster Panulirus argus in culture. J. Crustacean Biol. 28: 306-327.•Lyons, W. G. 1980. Possible sources of Florida’s spiny lobster population. Proc. Gulf Caribb. Fish. Inst. 33: 253-266.•Menzies, R.A., and, J.M, Kerrigan.1979. Implications of spiny lobster recruitment patterns of the Caribbean – A biochemical genetic approach. Proc. Gulf Caribb. Fish. Inst. 31: 164-178. Funding to support this work

was provided by NSF-TUES grant DUE-1043468

Background:•The Caribbean Spiny Lobster, Panulirus argus, population structuring is complicated by the long-range dispersal of the planktonic larvae, called phyllosoma.•Two theories of recruitment have been postulated, the Pan-Caribbean Panmictic theory (Lyons 1980) and the Closed System Theory (Menzies et al. 1979).•The Sargasso Sea may serve as critical habitat in acting as a corridor between distant populations.

Purpose:To investigate the influence of selected environmental parameters onphyllosoma distribution, as well as genetic and life stage structuring in theSargasso Sea in order to understand Panulirus argus population dynamics.

We would like to thank A. Siuda, A. Govindarajan and the faculty, staff, and students of SEA cruise C252. Genomic DNA was sequenced at the W. M. Keck Ecological and Evolutionary Genetics Facility at the Josephine Bay Paul Center of the Marine Biological Laboratory, Woods Hole, MA. Funding to support this work was provided by NSF-TUES grant DUE-1043468.

Biodiversity of hydroid communities associated with pelagic Sargassum Kiah Walker1, 2 and Allison Work1, 3

1Sea Education Association, Woods Hole, MA, 2Williams College, Williamstown, MA, 3Whitman College, Walla Walla, WA

Introduction

Methods

Hypotheses

Acknowledgements

Results and Discussion

Literature Cited

Conclusions

Figure 1. Sampling locations of Sea Education Association cruise C252. Red diamonds indicate sampling locations with S. fluitans exclusively, yellow indicates locations with S. natans exclusively, and orange indicates locations with both. White diamonds indicate locations where no Sargassum was found. In total, 25 clumps of S. fluitans and 51 clumps of S. natans were analyzed.

Figure 2. Hydroid species occurrences on S. fluitans and S. natans. Occurences are expressed as percent of total clumps on which each hydroid species was found. Findings are consistent with past studies. Calder (1995) also found that A. latecarinata was the most common species on S. fluitansand that C. noliformis was the most common species on S. natans. Calder (1995) identified a total of ten hydroid species on pelagic Sargassum when sampling in March, April, September, and December, including five of the six species found in this study.

A

B Figure 3. Hydroid species occurrences on S. fluitans (A) and S. natans (B) in the South and North Sargasso Sea. Occurences are expressed as percent of total clumps on which each hydroid species was found. Differences in hydroid species composition in the South and North Sargasso Sea may be related to the origin of Sargassum substrates. Sargassum in the North Sargasso Sea may have been carried there by the Gulf Stream after originating in the Gulf of Mexico (Gower and King 2011).

Table 1. Dominant and co-occurring species of hydroids. Dominance was based on estimated coverage of hydroid species on each clipping. Two clumps with three species of co-occurring hydroids were excluded from the matrix. One clump of S. natans included C. noliformis (dominant), L. flexuosa, and H. diaphana. One clump of S. fluitans included A. latecarinata (dominant), O. dichotoma, and L. flexuosa. Calder (1995) found the same primary dominants on each type of Sargassum.

Marine hydroids (Cnidaria, Hydrozoa) live in both coastal and open ocean regions throughout the world. In the Sargasso Sea, hydroids colonize the two types of pelagic Sargassum, Sargassum fluitans and S. natans. This study assessed species diversity and geographic distribution of hydroids living on these substrates. Hydroids were collected along a cruise track from Puerto Rico to Bermuda and Bermuda to New York during April and May 2014. Hydroids were identified morphologically, and forty samples were analyzed using sequences from the 16S ribosomal RNA gene. Hydroid species composition differed between the two species of Sargassum, as four hydroid species were found on both types of Sargassum, and two were exclusive to S. natans. Aglaophenia latecarinata was the dominant species on S. fluitans, while Clytia noliformis was the dominant species on S. natans. Hydroid species distribution also varied with latitude, as more species were found in the North Sargasso Sea. Additionally, genetic analysis of C. noliformis suggests two groupings of distinct haplotypes, which may be related to geographic origin of Sargassum substrates.

� S. fluitans and S. natans, both holopelagic macroalgae, are a primary source of substrate, habitat, protection, and food for a variety of organisms in the Sargasso Sea � Hydroids provide food for Sargassum-associated organisms such as fish, sea spiders, polychaetes, snails, and the endemic crab Planes minutus (Butler et al. 1982; Coston-Clements 1991) � A previous study conducted at Bermuda found ten species of hydroids on pelagic Sargassum, two of which were exclusive to S. fluitans and three of which were found on most thalli of both Sargassum species (Calder 1995) � This study contributes to improved understanding and documentation of Sargassum communities in the Sargasso Sea through morphological identification and genetic analysis of hydroids across a range of latitudes

� Hydroid species composition differs between S. fluitans and S. natans � Hydroid species distribution varies geographically

� Sargassum samples were collected at noon and midnight throughout SEA cruise C252 aboard the SSV Corwith Cramer � Midnight tows consisted of a 1 nautical mile Neuston tow; noon tows included a Neuston tow of the same duration and opportunistic dip net sampling � At each sampling location, two 10 cm thalli were clipped from the first three clumps of each Sargassum species for hydroid analysis � Hydroids were identified morphologically and percent coverage of each species was estimated � 16S ribosomal RNA genetic sequences were obtained from 40 hydroid samples

Hydroid species are important components of marine food web interactions in the Sargasso Sea. Differences in hydroid distribution may affect the feeding habits of larger organisms. By assessing hydroid diversity across latitudes in the Sargasso Sea, this study of hydroid distribution increases understanding of the entire Sargasso Sea ecosystem. This ecosystem is the subject of current management and conservation endeavors, but these efforts focus on only a subsection of the region. Differences in hydroid distribution suggest a broader conservation area may be necessary to protect complete Sargasso Sea food webs.

Dominant Species

Co-occurring Species

A. latecarinata C. noliformis L. flexuosa O. dichotoma P.

strictocarpa

A. latecarinata 0 1 0 0 0

C. noliformis 0 0 0 3 1

L. flexuosa 0 4 0 0 0

O. dichotoma 3 15 0 0 0

P. strictocarpa 0 1 0 0 0

No co-occurring species

18 22 0 0 0

� Hydroid species composition differs between Sargassum species � Hydroid species composition varies geographically, with greater species diversity in the North Sargasso Sea � Future research could further address genetic variation of hydroids throughout the North and South Sargasso Sea

Butler, J. N., B. F. Morris, J. Cadwallader, and A. W. Stoner. 1982. Studies of Sargassum and the Sargassum community. Bermuda Biological Station for Research. 22: 1-85.

Calder, D. 1995. Hydroid assemblages on holopelagic Sargassum from the Sargasso Sea at Bermuda. Bulletin of Marine Science. 56: 537-546.

Coston-Clements, L., L. R. Settle, D. E. Hoss, and F. A. Cross. 1991. Utilization of the Sargassum habitat by marine invertebrates and vertebrates–a review. NOAA Technical Memorandum NMFS-SEFSC-296.

Gower, J.F.R. and S. A. King. 2011. Distribution of floating Sargassum in the Gulf of Mexico and the Atlantic Ocean mapped using MERIS. International Journal of Remote Sensing. 32: 1917-1929.

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A. latecarinataC. noliformisH. diaphanaL. flexuosaO. dichotomaP. strictocarpaNo hydroids present

Figure 4. Haplotype network of 16S rRNA sequences of 21 C. noliformis samples collected between Puerto Rico and Bermuda. Circles represent unique haplotypes, and circle size is proportional to the number of individuals sharing a particular haplotype. Green indicates samples collected in the South Sargasso Sea, and blue indicates samples from the North Sargasso Sea. Each line segment represents a single nucleotide change. Results indicate two distinct haplotype groupings of C. noliformis. Eight of twelve samples from the South Sargasso Sea were the same haplotype. A separate haplotype was shared by five individuals, four of which were from the North Sargasso Sea. Haplotype differences suggest that Sargassum in the North and South Sargasso Sea may originate in different locations. All but one sample was collected from S. natans. Sample 017-NT-2A was collected from a clump of S. fluitans.

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017-NT-2A

Figure 5. Samples of each hydroid species collected in this study. Species pictured are: Aglaophenia latecarinata (a), Clytia noliformis (b), Halopteris diaphana (c), Laomedea flexuosa (d), Obelia dichotoma (e), Plumularia strictocarpa (f). Scale bar in all photos is 1 mm.

Abstract

a b

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Policy Implications

nd

Leptocephali Biodiversity in the Sargasso Sea: Spatial and Diel PatternsLuke Gervase1, 2, Callie Bateson1, 3, Gracie Ballou1, 4

1Sea Education Association, Woods Hole, MA, 2State University of New York College of Environmental Science and Forestry, Syracuse, NY, 3Rollins College, Winter Park, FL, 4University of Vermont, Burlington, VT

AbstractA diverse range of threatened and endemic species depend on the Sargasso Sea for migration and spawning due to its biophysical characteristics and central location in the Atlantic Ocean. Many species of eels, which make up an integral part of global fisheries and reef ecology, migrate to the Sargasso Sea to spawn. Eel larvae, known as leptocephali, are distributed throughout the Atlantic Ocean by surrounding currents. This study documents the distribution of leptocephali species found in the Sargasso Sea and uses molecular methods to evaluate the existence of two morphologically distinct and geographically separate populations of Bandtooth conger eel (Ariosoma balearicum). Tows were completed twice daily at depth and at the surface along a cruise track between Puerto Rico and New York City. The greatest biodiversity was observed at depth during night tows suggesting vertical migration occurs to a greater depth than previously thought. Myomeres are muscle striations corresponding with vertebra that are commonly used for morphological identification in eel species. Myomere counts supported the presence of two populations of A. balearicum, however, genetic analysis of species divergence within the 16S rRNA gene was inconclusive. Additional gene and primers sets were tested for A. balearicum for application in future population genetics studies with this species. The likely existence of two spawning populations of A. balearicum warrants further investigation and must be considered in future conservation efforts to protect the biodiversity of the Sargasso Sea.

Results & Discussion Results & Discussion

Conclusions•Overall, leptocephali species diversity was found to be the highest at depth

during the night. A. balearicum were the most abundant species at both depth and in surface tows•Morphological data of myomere counts and total length averages suggests

two breeding populations of A. balearicum. Genetic analysis was unable to support this claim however, RGA1, cytb, and EGR3 show promise for future population genetics studies

Policy ImplicationsThis project has implications for improved eel fisheries management and proper conservation of biodiversity within the Sargasso Sea. The study of leptocephali length along the cruise track aids in finding the spawning sites for commercially important species. These hotspots for conservation must be addressed when creating policies to protect the vulnerable eel larvae. If further research confirms two populations of A. balearicum exist, policies must be enacted to preserve their biodiversity.

Acknowledgements & ReferencesThe authors would like to acknowledge and thank students and staff of the 2014 SEA Semester Marine Biodiversity and Conservation program. Special thanks to A. Siuda and C. Dykeman for advising this study, L. Blanco Bercial, A. Bucklin, L. Amaral-Zettler, M. Miller, and R. Hanel for assistance in genetic analysis methods, and 2013 MBC students for providing additional leptocephali tissue samples. Funding to support this project was provided by NSF-TUES grant DUE-1043468.

Miller, M.J. 2009. Ecology of Anguilliform Leptocephali: Remarkable Transparent Fish Larvae of the Ocean Surface Layer.Aqua-BioSci. Monogr. 2.4: 1-94.Miller, M.J. 2002. Distribution and ecology of Ariosoma balearicum (Congridae) leptocephali in the westernNorth Atlantic. Environ. Biol. Fish. 63: 235-252.

Background• Eel species migrate from coastal and continental shelf regions along the

Atlantic coast to spawn in the Sargasso Sea• Currents within the Sargasso Sea influence the dispersal of leptocephali and

spawning strategies of adult eels • A. balearicum is an oceanodromous eel species commonly found in the

Sargasso Sea. Previous studies have focused on morphological characteristics but have lacked genetic research to support divergent populations

Methods• Eel larvae were collected on S.E.A. cruise C252 aboard the SSV Corwith

Cramer from 14 April 2014 to 17 May 2014• Stacked tows were completed at 12:00 h and 00:00 h daily (Table 1)• Total length and myomere counts were measured for all A. balearicum• Tissue was excised posterior to skull above notochord on select samples.

16S rRNA, cytb, MYH6, RGA1, EGR2B, and EGR3 genes from A. balearicumwere amplified

• Voucher samples were preserved in 10% formalin• A Shannon index was calculated to quantify diversity at each station

Day depth range

Night depth range

Neuston net Surface Surface1-Meter ring net

64 to 75 m 7 to 15 m

2-Meter ring net

100 to 165 m 28 to 71 m

Concl

Figure 8: Neighbor- joining phylogeny tree created using MEGA6. Divergence is shown between northern (shaded circles) and southern (clear circles) populations of A. balearicum based on the 16S rRNA gene. Genetic analysis was unable to support the presence of northern and southern breeding populations in the Sargasso Sea. The 16S rRNA gene used in PCR sequencing may be too conservative to represent possible divergence between populations. Select primer sets for RGA1, cytb, and EGR3 resulted in successful PCR. PCR results for MYH6 and EGR2B were inconclusive.

Figure 6: As expected, the average length (mm) of A. balearicum leptocephali increased with increasing latitude. This finding supports the spawning location of A. balearicum in the southwest Sargasso Sea. A drop in length averages just north of the Sub Tropical Convergence Zone (STCZ ~27°N) suggests two breeding populations of A. balearicum. A t-test revealed a statistically significant difference in average total length between southern and northern populations (p= 0.00049).

Figure 7: The analysis of myomeres determined a statistically significant (t-test p= 4.56 * 10-9) difference between individuals collected at stations to the north and south of the STCZ. This is an expected result based on current and dispersal patterns. This data suggests two breeding populations of A. balearicum. Stars represent median myomere counts. Table 1: Target sampling depths

for day and night stack towsFigure 3: Illustration showing the location of tissue excision

y = 0.6373x + 72.868R² = 0.1608

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H1: Leptocephali diversity will be greater at the surface during the night than at depth during the day.H2 :Average total length of leptocephali will increase with increasing latitude and distance from suggested spawning areasH3: The North and South Sargasso Sea regions host morphologically and genetically distinct populations of A. Balearicum

Figure 1: Photographs showing morphological variability of head and jaw structure for 15 types of anguilliform leptocephali (Miller 2009).

Figure 5: Temporal and depth variability in Shannon Diversity Index. The highest leptocephali species biodiversity was found consistently at surface depths during night tows. These results suggest an incorrect estimation of diel migration for smaller larvae. Error bars are representative of standard error.

0.597

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Time and Depth of TowFigure 2: Head of an A. balearicumleptocephalus Figure 4: Distribution of leptocephali

families across 17 stations along the cruise track. Small blue dots indicate the location of stations. Pie charts indicate percentage of each family caught at each station.

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Many mysteries still surround the world of marine biodiversity. Microbes compose a huge portion of the organisms in the marine environment, but little is known about their behavior, abundance, and diversity. This study focuses on the diversity and distribution of Vibrio species. Many known and unknown species of Vibrio bacteria exist in the ocean, and some, such as V. cholerae, are known to be pathogenic. Vibrio live not only in sea water, but also on floating biotic and abiotic substrates. In order to better understand the qualities of these bacteria samples of plastic, sea water, and Sargassum were taken from different stations across the latitudinal gradient of the Sargasso Sea. Samples were measured for morphotype diversity. After isolating specific colonies, DNA from specific samples was extracted and sequenced. We hypothesized that differences in morphotype diversity would occur among the three mediums. Of the bacteria colonies studied, morphological and genetic differences were found in the bacteria among the different substrates as well as between the different locations along the latitudinal gradient. While the data collected indicates some morphotypes of Vibrio are substrate and location specific, further research is needed to fully assess the implications of this study. Many variables need to be considered when making predictions about Vibrio substrate and location specificity.

Abstract

Methods

Results & Discussion

Conclusions � In the Sargasso Sea, a majority of the morphtypes are

rare occurring with only a few common morphotypes.

� Sea water has the greatest diversity of morphotypes, followed by Sargassum, and then by plastic debris.

� Majority of the Vibrio morphotypes are substrate specific; about 10% of all morphotypes are found on all three substrates.

� A correlation appears to exist between latitude and the morphotype richness on plastic debris and Sargassum. However, this was not observed for sea water.

� A clear and gradual change in morphotype composition across the latitudinal gradient was observed.

� There are genetic differences of the Vibrio colonies across different samples

� We recommend further research on Vibrio and the microbial community in the open ocean

Policy Implications This study has provided a preliminary understanding of Vibrio biodiversity in open-ocean ecosystems. As abiotic factors such as anthropogenic debris pollution and sea surface temperature continue to change, the potential negative effects Vibrio can have on human health and commercial marine species make them important organisms to study and understand. Furthering our knowledge on the diversity of Vibrio and other relevant microbes in the Sargasso Sea can, in the future, raise awareness of the growing need for better education and management of our oceans and seas.

Acknowledgements The funding to support this work was provided by NSF-TUES grant DUE-1043468. We would like to thank Sea Education Association (SEA) for making this research project possible and to Dr. Amy NS Siuda, Dr. Erik R Zettler, Dr. Linda Amaral-Zettler, and Annie Scofield, whose advice, feedback and comments much improved our research and paper.

� Collected plastic debris, Sargassum, and sea water samples daily from noon neuston station at different latitudes in the Sargasso Sea

� Stamped samples on CHROMagar™ Vibrio to select for Vibrio species

� After 48 hours of growth on CHROMagar™, the morphoptypes were identified using a morphotype description key

� Vibrio colonies of interest (49 colonies) were transferred to Tryptone Sea Water plates for isolated growth

� DNA was extracted with Lyse and Go reagent and then amplified by PCR and sequenced for the 16S rRNA gene

� Sequenced DNA was aligned and trimmed to compare with known Vibrio species and analyzed with BLAST

Allison Adams 1,2, Cheng Cheng1,3 , Ben Ong1,4 , Yip Ye1,5 1Sea Education Association, Woods Hole, MA, 2Syracuse University, Syracuse, NY, 3Knox College,

Galesburg, IL, 4Rice University, Houston, TX, 5Macalester College, Saint Paul, MN

A Study of the Biodiversity of Vibrio Bacteria in the Sargasso Sea

Figure 3. Number of morphotypes of Vibrio bacterial colonies isolated from plastic, Sargassum, and seawater in the Sargasso Sea across the latitudinal gradient ranging from 18.67° to 37.44°. An overall decreasing trend in morphotype richness in plastic and Sargassum was observed, which could be associated with the falling sea surface temperature. With regards to seawater, no observable trends could be identified.

Figure 1. Rank-abundance curve for the 53 bacterial colony morphotypes observed from samples collected at neuston tow stations in the Sargasso Sea stations between St. Croix, USVI and Woods Hole, MA. This graph shows that a majority of the morphotypes were rare with a few commonly occurring morphotypes.

Figure 2. Morphotype accumulation curves of Vibrio bacterial colonies found on plastic, Sargassum and sea water. It suggests that seawater has the greatest diversity of morphotypes, followed by Sargassum and then by plastic debris. Also, there is no sign of plateauing for the seawater accumulation curve.

Figure 4. Distribution of substrate specificity of the Vibrio morphotypes found on plastic, Sargassum, and seawater in the Sargasso Sea. A majority of the morphotypes were substrate specific with approximately 10% being completely non-specific

Figure 5. Changes in the diversity and abundance of morphotypes that occurred at least 4 times across the latitudinal gradient. There is an obvious change in morphotype composition.

DNA Analysis

Figure 7. A DNA Alignment with MEGA software of 5 consensus sequence from Vibrio samples compared against 4 known Vibrio species. Samples are Vibrio bacteria and are genetically different.

C-241 Cruise Track and location of all Neuston Tow Stations

Vibrio bacteria growing on CHROMagar™ Vibrio after 48 hours